Ingot mold and ingot



May 15, 1923.

' E. GATHMANN Filed July l5. 1922 remita May' is, reas.,

attain are,

EMIL GATHMANN, 0F BALTIMORE, MARYLAND.

INGo'r MOLD AND meer.'

Application led July `15, 1922. Serial No. 575,312.

To all t may concern `Be-it known that I, EMIL GATHMANN, a citizen 'of tthe United States, residing in Baltimore city, State of Maryland, haveinvented certain new and useful Improvements in Ingot Molds yand lngots,of which the following is a specification.

This invention relates to the casting of ingots from eil'ervescing orgassy steel and 1t involves certain improvements in the construction ofthe mold and in the method of manufacture.

The improved mold is illustrated in the accompanying drawings which showa vertical section of a metal ingot ymold embodying my improvements.

VThe major part A of the mold is of the well known Gathmann type shownin patents heretofore granted to me, of which my latest Patent No.1,419,454 of June 13, 1922, may be taken as an example. Such molds areusuall bi end up molds constructed to cool t e mo ten metal more quicklyin the lower portion of the mold than'in the upper portion thereof as bymaking the lower mold walls thicker and of greater heat absorbingquality. In such molds, in order to reduce piping, provision has beenmade to conserve the heat of the ingot at its upper end as by making themold walls thinner at the topor by providing heat insulating means forthe upper portion of the ingot. The part A is formed, as shown, with abottom opening a closed by a plug a and `a sealing plate a2 of the kindshown in my patent of June 13, 1922. The mold walls are rounded ornecked in at a as also'shown in said patent. The part A of the mold isformed with lugs a3, a4 by means of which it may be lifted or supportedwhile being raised or transported.

Instead of employing a top section of refractory material as -heretoforeto conserve the heat of thewtop portion ofy the ingot,- I employ,according to my present invention, a metallic mold top portion T whichis adapted to chill the upper part of the ingot by absorbing the\heattherefrom for a purpose hereinafter described. This top portion isflanged at t to provide a part which eX- tends to a slight distance intothe lower mold section and a part t which rests on the top of the moldsection A, as shown in my patent No. 1,192,617 of July 25, 1916. l

Molten'steel, as it is teemedi'into the ingot forming mold, in so farxas freedom from oecluded gases is concerned, may be broadly separatedinto two kinds. These are generally known as effervescing or gassy steeland .none'ervescing or deoxidized steel.

My present invention relates primarily to ymeans for moreeiicientlyproducing ingots made of gassyor elfervescing steel, 1. e.,steel containing a large volume of gases in solution due to theoxidation of the meta-l in the melting process carried on in Bessemerconverters, open-hearth furnaces and similar melting apparatus, andwhere the steel has not been fully finished or deoxidized before it ispoured into the mold.

During the cooling and solidiication of the ingot in a mold; thecontained gases are released as the cooler metal does not have the sameabsorptive or solvent power for the gases as it has when at a highertemperature andk while being poured into the mold. As the ingot metal inthe mold cools towards the critical line of solidication or so calledlfreezing, the contained gases are released from solution with the metaland as the ingot metal becomes pasty or partially solidified these gasesare entrapped in the body of the ingot metal within the mold and attimes cause the metal to 'boil and if means are not provided to freezeover the open or free surface at the top of the ingot, the volume of theingot would at times be materially enlarged bythe formation of numerousblow holes or gas pockets of varying sizes principally within the zoneof the outer skin of the solidifying or pasty ingot. It has, therefore,been the common practice to .freeze over the upper exposed surface ofthe ingot when made of gassy steel at an early stage of solidiication.Such freezing as previously practised has, however, not been sufficientto prevent a considerable increase in volume or a greatenheight orlength of the solidifying ingot as the chilling action has heretofore'type of steel. In steel well deoxidized, a

decrease in volume is ell'ected amounting to from three to six per centor more during the process of solidication. This latter kind ofsolidification has been so controlled by casting the molten metal ofthis type in ingot molds of the'kind shown, for instance, in my prior(patent of June 13, 1922, that the pipe or iscard is contained in theupper 3% to 8% of the ingot. From analyses of tests made by me it hasbeen shown that a 'big end up mold, i. e., one with a larger crosssection at the upper end,limproves the quality of the ingot producedtherein not only in thoroughly deoxidized steel but in the far largertonnage field of ingots which are now being produced of gassy oreffervescing steel. I have found, however, that a refractory shrink headfor conserving the heat of the ingot at its upper portion, such as Ihave used when working with well deoxidized steel is not efficient inthe production of ingots made of gassy steel. Therefore when workingwith `gassy steel I have avoided conserving heat at the upper end of theingot and instead provided means for chilling this portion of -theingot. The meanspreferably used for this purpose 1s what may be termed achill top. This is adapted to contain a greatly reduced section of theupper portion of the gassy steel ingot. yThe chill top referred/to isillustrated in the drawings at T. It consists of a heavy heat absorbingmold portion having aY chamber of materially contracted cross sectionalvolume or area relatively the average cross section of the body of the`ingot being formed, whereby the upper end of the ingot is chilled bythe rapid'absorption of its contained heat by the top mold section. Inthis way the upper portion of the ingot is made to solidify much .more

quickly than the body part thereof.

The top chill section shown is of such construction that it may bereadily applied to or removed from a mold and does not involvecomplicated apparatus for moving it.

rIlhe rapid freezing' or solidiication of the top of the ingot preventsor at least greatly retards or reduces the swelling or enlargement ofthe ingot body and the consequent 4Jformation of numerous blow holeswhich cause such swelling in ingots made in the usual way. y

Such blow holes as are formed in the ingotmade in accordance with myinvention are deep seated, i. e., locatedV at a considerable distancefrom the surface of the side walls of the ingot. Actual tests have'shownthat most of the blow holes are contained in the top or u per portion ofthe ingot which has been chi led and frozen by the chill top section ofthe mold.

The so called big end up mold when fitted with my improved metallic moldtop for chilling'and rapidly solidifying the top and upper side'portions ofthe ingot permits of the use of a much larger percentagethan heretofore of the entire ingot for commercial purposes, such assheet, bar, structural steel, and other steel products where the surfaceconditions are of primary importance. The entire body of an ingot formedin a mold having a chilling section of the kind shown in the drawingsmay be utilized with the exception of approximately one-half of one percentor less discard at the bottom of the ingot and approximately o-neand a half to three per cent at the top of the ingot for steel productwhere surface is of primary consideration and uniformity of interiorcondition is not of great importance. The decrease in the top crosssection of the ingot as also in the base portion as produced in myimproved lmold largely preventsor reduces the splitting of the ends ofthe ingot during the blooming or slabbing operations in the` rollingmills.

In the ordinary iiat bottom type of ingot mold from 2% to 3% of theingot is lost due to the so called fish tailing or splitting of the endsduring rolling, but by providing the mold with a rounded bottom as shownand heretofore described and with a contracted top adapted to chill thetop of the ingot, the'total discard in the rolling process due to fishtailing or splitting is greatly reduced.

The drawings illustrate diagrannnatically the appearance of the blowholes formed during solidication, and it will be pbserved that these arelargely confined to the top part of thel ingot within'the chill sectionof the mold. The shape of the ingot ends formed as heretofore explainedis such that relatively small cro at each end yis required. The blow hoes shown in the body of the ingot diagrammatically are not injurious,for product where surface 'is of prilnary importance.

It should be observed that inv order to get the best results the 4crosssectional area of the upper portion of the mold-chamber or chill headshould be less than half the mean cross sectional area of the body` ofthe chamber portion of the mold. The top portion of the mold or chillhead should have its walls contracted to surroundl at least one-tenth ofthe length of the ent-ire ingot and the walls of said top portion shouldbe of greater weight and volume than the weight and volume of thatportion of the ingot which is cast within it and the side walls definingthe lower chamber portion should have a downwardly in'- clined inwardlyextending necked-in contour to reduce the cross section at the' bottomof the ingot.

I claim as my invention:

1. An ingot moldhaving a metallic heat absorbing top portion adapted toform the upper part of ingot and to be removable from the main body ofthe mold and conl structed` to chill and thus quicklyy freeze lthe upperpart of the ingot.

2. A big-end-up ingot mold having a metallic heat absorbing top portionadapted to formthe upper art of the ingot and to chill and thus qulcklyfreezesaid upper portion.

3. A'big-end-up metallicl ingot mold hav ing the walls of its lowerportion constructed or equipped to promote the cooling of the lower'part of the ingot, and having an all-metallic top part constructed toform the upperend of the ingot and to rapidly chill saidupper partduring solidification to thus assemble blow holes lat the top of theingot. s,

4. An ingot mold having a rounded bottom and rounded lower side wallsadapted to rapidly cool the lower part of the ingot and having a topportion constructed to form the upper end of the ingot and .to chillsaid upper end rapidly during solidification. I

5. A metallic ingot mold provided with a necked-in or round bottom andhaving a vertical chamber, the cross sectional area of the upper portionof which is less than one-half of the mean cross sectional area of thebody of the chamber.

6. A metallic ingot mold having a contracted upper chamber constructedto hasten the chill and thus freeze the'upper portion 'of the moltenliquid ingot more rapidly than the freezing of the body portion of theingot, said mold chamber beinglprovided with a necked-in or roundedbottom whereby both the top portion and )the bottom portion of theingotwill be of less mean cross sectional area than the mean cross sectionalarea of the mold chamber.

An ingot mold having its top ingot forming chamber portion defined bymetal lic walls, said top portion having a mean cross section of lessarea'than the mean cross sectional area of the vertical mold chamber,

the said chamber being provided with a b ottom or base portion having a.rounded or a COIlCaJVO-'COIIVGX COIllJOllI'.

8. A metallic ingot mold provided with a concavo-convex bottom or baseportion and having a metallic heat absorbing top portion 4inclosmg avertical chamber adapted to form -the upper part of the ingot andconstructed to chill and thus quickly Jfreeze the vertical walls ofthevupper part of the ingot.

9. An ingotmold having its ingot forming chamber defined by heavymetallic ,heatabsorbing walls, the top and also the bottom portion ofthe ingot chamber having an area of less horizontal cross section, asdefined by the metallic heat absorbing walls, than that .of the bodyportion of said chamber, and the side walls defining `the lower chamberportion having a downward inwardly extending necked-in contourterminatingin 10. An ingot mold having its ingot forming chamber definedby heavy metallic heat absorbing walls, the top and also the bottomportion of the ingot chamber having an area of less horizontal crosssection as dened by the said metallic heat absorbing walls than that ofthe body portion of said chamber, and a. separable base portion forclosing the lower portion of the ingot chamber.

1l.v vertically extending ingot mold having substantially its entireingot forming chamber defined by heavy metallic heat absorbing walls,the upper as also the lower portions or sections of said chamber havinga necked-in contour, whereby an ingot formed in said chamber will haveits top and bottom ends of less horizontal Across section than the bodyof the ingot.

l2. A mold for forming and' rapidly chilling ingots which are made of agassy or partially deoxidized molten metal, the said mold beingYcharacterized by having its vertically extending and also its bottomWall portions defining the mold chamber constructed of heavy metallicheat absorbing material, the upper and lower sections ot said chamberhaving a mean horizontal cross sectional area considerably less thanthat of the body portion of said chamber.

13. An ingot cast in` a chill mold throughout its length and having atop and bottom portion of less horizontal cross sectional area than thatof the intermediate. body portion of the ingot, the base surface portionbeing substantially flat and merging into the lower portion of the ingotby means of a necked-in contour. y

14. An ingot produced from a gassy or partially deoxidized molten metalcast in a chill mold throughout its vertical length, having a top andbottom portion of materially less horizontal cross sectional area thanthat ofthe intermediate body portion of the ingot, the base of thebottom portion of the ingot being formed or defined by a relatively thinflat metallic late, which is welded orattached to the said base by thecasting of the said ingot.

15. An ingot produced from gassy or partially deoxidized molten metalhaving its lower, its body and its vertically extending f top portionsformed in an ingot moldcham- `ber defined by heat absorbing metallicwalls,

the lower and the top portions of said ingot having an area of lesshorizontal cross section than that of the body portion of the ingot andthe side walls defining the lower portion of the ingot havln Vlili IiP/0splitting or fshtailing of thel upper and lower end portions of theingot during: its blooming or slabbing in the rolling mill is reduced,Which consists in accelerating the isolidification of the upper and,lower ingot portions by means of upper and lower heavy chambered chillseach of which is of less cross sectional area than the middle portion ofthe mold chamber therebymolding the said upper and lower portions of theingot in seid chill with less mean cross sectional area. and lesstransverse dimensions than that of the body of the ingot.

In testimony whereof, I have hereunto subscribed my name.

EMIL Giifrrnmim`

